當本地的原始碼樹已與特定版本的 FreeBSD 如 FreeBSD-STABLE 或 FreeBSD-CURRENT 同步以後,便可使用原始碼樹來重新編譯系統。這個程序即為重新編譯 World。
在重新編譯 World 之前,請確定已完成以下工作:
備份所有重要的資料到另一個系統或可卸除的媒體,檢查備份的完整性並在手中保留一份可開機的安裝媒體。如何強調都不足夠說明在重新編譯系統 之前 備份系統的重要性。即便重新編譯 World 已變成簡單的一件事,也難免會有原始碼樹失誤導致系統無法開機的時候。您可能永遠都用不上備份,但最好確保安全而非後悔。
回顧最近 freebsd-stable 或 freebsd-current 中的項目,依您所追蹤的分支決定。注意任何已知的問題以及會被影響的系統。若已知的問題影響您已同步的原始碼版本,請等候表明問題已被解決的 “全部解決 (all clear)” 公告發佈,然後重新同步原始碼並確認本地的原始碼版本已含有所需的修正。
閱讀 /usr/src/UPDATING
了解該版本的原始碼是否有必要的額外步驟要完成。 這個檔案中會包含有關潛藏問題的重要資訊,並且可能會要求執行某些指令。大多升級需要完成指定的額外步驟,例如:在安裝新 World 前重新命名或刪除指定檔案,這些步驟會列在檔案最後,明確說明目前建議的升級順序。若 UPDATING
中有與本章相矛盾的步驟,請以 UPDATING
為準並應遵循其內容。
make world
: 部份舊版的文件建議使用 make world
。然而該指令跳過了部份重要的步驟,應僅供專家使用。大多數的情況使用 make world
都是錯的,並應使用此處說明的程序。
編譯 World 流程會假設您是依照 節 23.5, “同步原始碼” 指示取得最近版本的原始碼來升級舊版的 FreeBSD。
在 FreeBSD,“world” 一詞包含了核心,核心系統 Binary,程式庫,原始碼以及內建的編譯器。這些元件編譯與安裝的順序非常重要。
舉例來說,舊的編譯器可能有問題而無法編譯新的核心。新的核心需使用新的編譯器來編譯,因此新的編譯器必需先編譯,但在新核心編譯前並不一定要安裝。
新的 World 可能需要使用新的核心功能,所以必須在新的 World 安裝之前先安裝新的核心。舊的 World 也可能在新的核心上無法正常執行,所以必須在新的核心安裝完之後 馬上安裝新的 World。
有一部份設定必須在新的 World 安裝前變更,但其他的部份在之前變更則可能會破壞舊的 World。因此會使用到兩種不同的設定升級步驟。大部份情況,更新程序只會取代或新增檔案,不會刪除已存在的舊檔案。當這可能會造成問題時 /usr/src/UPDATING
便會說明需要手動刪除的檔案以及操作的步驟。
這些問題會影響接下來的建議升級順序。
將執行 make
的輸出儲存到檔案是不錯的辦法,若發生錯誤時,便可複製錯誤訊息張貼到 FreeBSD 郵遞論壇。
最簡單的方式是使用 script
並透過參數指定要儲存所有輸出的檔案名稱。請不要儲存輸出到 /tmp
,因這個目錄可能在下次重新開機後被清除。儲存檔案最好的地方是 /var/tmp
。在重新編譯 World 之前執行這個指令,並在流程完成後輸入 exit
:
#
script /var/tmp/mw.out
Script started, output file is /var/tmp/mw.out
編譯 World 流程中使用的指令應依此處指定的順序執行。本節將摘要各指令的功能。
若編譯 World 流程先前已在系統執行過,先前編譯的結果可能遺留在 /usr/obj
。要加速新的編譯 World 流程及節省處理相依問題的時間,若此目錄存在,請移除此目錄:
#
chflags -R noschg /usr/obj/*
#
rm -rf /usr/obj
編譯新的編譯器及一些相關工具,然後使用新的編譯器編譯新的 World。編譯的結果會儲存到 /usr/obj
。
#
cd /usr/src
#
make buildworld
使用在 /usr/obj
中的新編譯器來編譯新的核心,來確保不會發生編譯器與核心不相容的問題。因某些記憶體結構可能有修改,這個步驟是必要的,若核心與原始碼的版本不同,ps
及 top
這類的程式會無法運作。
#
make buildkernel
安裝新的核心與新的核心模組,讓開機時可以使用新的核心。這個指令可在多使用者模式執行,除非 kern.securelevel
設定在 1
以上 且 在核心 Binary 有設定 noschg
或類似的旗標 (Flag),請先讓系統進入單使用者模式。請參考 init(8) 取得有關 kern.securelevel
的詳細資訊以及 chflags(1) 取得有關各種檔案旗標的詳細資訊。
#
make installkernel
讓系統進入單使用者模組來減少升級任何已在執行中的 Binary 所產生的問題,同樣也可減少在新核心上執行舊 World 的問題。
#
shutdown now
進入單使用者模式後,若系統磁碟格式為 UFS 請執行以下指令:
#
mount -u /
#
mount -a -t ufs
#
swapon -a
若系統磁碟格式為 ZFS,則需執行以下兩個指令。此範例假設 zpool 名稱為 zroot
:
#
zfs set readonly=off zroot
#
zfs mount -a
選用:若想要使用 US 英文以外的鍵盤對應表,可以使用 kbdmap(1) 來變更:
#
kbdmap
接著,不論那一種檔案系統,若 CMOS 時鐘設定為本地時間 (若 date(1) 顯示不正確的時間與時區),請執行:
#
adjkerntz -i
重新編譯 World 不會直接更新某些目錄中的設定檔,如 /etc
, /var
以及 /usr
。接下來的步驟是更新一部份的設定檔到 /etc
來準備安裝新的 World。以下指令只會比對影響 installworld
是否成功執行的必要檔案。例如,這個步驟會可能會加入新版 FreeBSD 的新群組、系統帳號或啟動 Script。為了讓 installworld
步驟可以使用任何新的系統帳號、群組與 Script,這是個必要的步驟。請參考 節 23.6.4, “合併設定檔” 來取得更多有關此指令的詳細操作說明:
#
mergemaster -p
從 /usr/obj
安裝新 World 與系統 Binary。
#
cd /usr/src
#
make installworld
更新任何剩下的設定檔。
#
mergemaster -iF
刪除任何過時的檔案。這很重要,因為若檔案遺留在磁碟上可能會造成問題。
#
make delete-old
現在需要完整重新啟動來載入新的核心、新的 World 與新的設定檔。
#
reboot
確認所有已安裝的 Port 在舊的程式庫移除前已依照 節 4.5.3, “升級 Port” 的說明重新編譯。當重新編譯完成後,移除過時的程式庫來避免與新的程式庫發生衝突。有關此步驟更詳細的說明請參考 節 23.6.5, “刪除過時的檔案及程式庫”。
#
make delete-old-libs
若系統允許停機一小段時間,請考慮以單使用者模式編譯系統來替代在多使用者模組編譯系統,然後進入單使用者模式來完成安裝。重新安裝系統會觸及到很多重要的系統檔案,所有的標準系統 Binary、程式庫以及引用檔。在執行中的系統更換這些檔案,特別是有使用者在使用時,是自找麻煩。
This build world process uses several configuration files.
The Makefile
located in
/usr/src
describes how the programs that
comprise FreeBSD should be built and the order in which they
should be built.
The options available to make
are
described in make.conf(5) and some common examples are
included in
/usr/share/examples/etc/make.conf
. Any
options which are added to /etc/make.conf
will control the how make
runs and builds
programs. These options take effect every time
make
is used, including compiling
applications from the Ports Collection, compiling custom C
programs, or building the FreeBSD operating system. Changes to
some settings can have far-reaching and potentially surprising
effects. Read the comments in both locations and keep in mind
that the defaults have been chosen for a combination of
performance and safety.
How the operating system is built from source code is
controlled by /etc/src.conf
. Unlike
/etc/make.conf
, the contents of
/etc/src.conf
only take effect when the
FreeBSD operating system itself is being built. Descriptions of
the many options available for this file are shown in
src.conf(5). Be cautious about disabling seemingly
unneeded kernel modules and build options. Sometimes there
are unexpected or subtle interactions.
The general format for using make
is as
follows:
#
make -x
-DVARIABLE
target
In this example,
-
is an option
passed to x
make
. Refer to make(1) for
examples of the available options.
To pass a variable, specify the variable name with
-D
. The
behavior of the VARIABLE
Makefile
is controlled by
variables. These can either be set in
/etc/make.conf
or they can be specified
when using make
. For example, this
variable specifies that profiled libraries should not be
built:
#
make -DNO_PROFILE target
It corresponds with this setting in
/etc/make.conf
:
NO_PROFILE= true # Avoid compiling profiled libraries
The target
tells
make
what to do and the
Makefile
defines the available targets.
Some targets are used by the build process to break out the
steps necessary to rebuild the system into a number of
sub-steps.
Having separate options is useful for two reasons. First,
it allows for a build that does not affect any components of a
running system. Because of this,
buildworld
can be safely run on a
machine running in multi-user mode. It is still recommended
that installworld
be run in part in
single-user mode, though.
Secondly, it allows NFS mounts to be used to upgrade multiple machines on a network, as described in 節 23.7, “多部機器追蹤”.
It is possible to specify -j
which will
cause make
to spawn several simultaneous
processes. Since much of the compiling process is
I/O-bound rather than
CPU-bound, this is useful on both single
CPU and multi-CPU
machines.
On a single-CPU machine, run the following command to have up to 4 processes running at any one time. Empirical evidence posted to the mailing lists shows this generally gives the best performance benefit.
#
make -j4 buildworld
On a multi-CPU machine, try values
between 6
and 10
to see
how they speed things up.
If any variables were specified to make
buildworld
, specify the same variables to
make installworld
. However,
-j
must never be used
with installworld
.
For example, if this command was used:
#
make -DNO_PROFILE buildworld
Install the results with:
#
make -DNO_PROFILE installworld
Otherwise, the second command will try to install
profiled libraries that were not built during the
make buildworld
phase.
FreeBSD provides the mergemaster(8) Bourne script to aid
in determining the differences between the configuration files
in /etc
, and the configuration files in
/usr/src/etc
. This is the recommended
solution for keeping the system configuration files up to date
with those located in the source tree.
Before using mergemaster
, it is
recommended to first copy the existing
/etc
somewhere safe. Include
-R
which does a recursive copy and
-p
which preserves times and the ownerships
on files:
#
cp -Rp /etc /etc.old
When run, mergemaster
builds a
temporary root environment, from /
down,
and populates it with various system configuration files.
Those files are then compared to the ones currently installed
in the system. Files that differ will be shown in
diff(1) format, with the +
sign
representing added or modified lines, and -
representing lines that will be either removed completely or
replaced with a new file. Refer to diff(1) for more
information about how file differences are shown.
Next, mergemaster
will display each
file that differs, and present options to: delete the new
file, referred to as the temporary file, install the temporary
file in its unmodified state, merge the temporary file with
the currently installed file, or view the results
again.
Choosing to delete the temporary file will tell
mergemaster
to keep the current file
unchanged and to delete the new version. This option is not
recommended. To get help at any time, type
? at the mergemaster
prompt. If the user chooses to skip a file, it will be
presented again after all other files have been dealt
with.
Choosing to install the unmodified temporary file will replace the current file with the new one. For most unmodified files, this is the best option.
Choosing to merge the file will present a text editor, and the contents of both files. The files can be merged by reviewing both files side by side on the screen, and choosing parts from both to create a finished product. When the files are compared side by side, l selects the left contents and r selects contents from the right. The final output will be a file consisting of both parts, which can then be installed. This option is customarily used for files where settings have been modified by the user.
Choosing to view the results again will redisplay the file differences.
After mergemaster
is done with the
system files, it will prompt for other options. It may prompt
to rebuild the password file and will finish up with an option
to remove left-over temporary files.
As a part of the FreeBSD development lifecycle, files and
their contents occasionally become obsolete. This may be
because functionality is implemented elsewhere, the version
number of the library has changed, or it was removed from the
system entirely. These obsoleted files, libraries, and
directories should be removed when updating the system.
This ensures that the system is not cluttered with old files
which take up unnecessary space on the storage and backup
media. Additionally, if the old library has a security or
stability issue, the system should be updated to the newer
library to keep it safe and to prevent crashes caused by the
old library. Files, directories, and libraries which are
considered obsolete are listed in
/usr/src/ObsoleteFiles.inc
. The
following instructions should be used to remove obsolete files
during the system upgrade process.
After the make installworld
and the
subsequent mergemaster
have finished
successfully, check for obsolete files and libraries:
#
cd /usr/src
#
make check-old
If any obsolete files are found, they can be deleted using the following command:
#
make delete-old
A prompt is displayed before deleting each obsolete file.
To skip the prompt and let the system remove these files
automatically, use
BATCH_DELETE_OLD_FILES
:
#
make -DBATCH_DELETE_OLD_FILES delete-old
The same goal can be achieved by piping these commands
through yes
:
#
yes|make delete-old
Deleting obsolete files will break applications that
still depend on those obsolete files. This is especially
true for old libraries. In most cases, the programs, ports,
or libraries that used the old library need to be recompiled
before make delete-old-libs
is
executed.
Utilities for checking shared library dependencies include sysutils/libchk and sysutils/bsdadminscripts.
Obsolete shared libraries can conflict with newer libraries, causing messages like these:
/usr/bin/ld: warning: libz.so.4, needed by /usr/local/lib/libtiff.so, may conflict with libz.so.5
/usr/bin/ld: warning: librpcsvc.so.4, needed by /usr/local/lib/libXext.so, may conflict with librpcsvc.so.5
To solve these problems, determine which port installed the library:
#
pkg which /usr/local/lib/libtiff.so
/usr/local/lib/libtiff.so was installed by package tiff-3.9.4
#
pkg which /usr/local/lib/libXext.so
/usr/local/lib/libXext.so was installed by package libXext-1.1.1,1
Then deinstall, rebuild, and reinstall the port. To automate this process, ports-mgmt/portmaster can be used. After all ports are rebuilt and no longer use the old libraries, delete the old libraries using the following command:
#
make delete-old-libs
If something goes wrong, it is easy to rebuild a
particular piece of the system. For example, if
/etc/magic
was accidentally deleted as
part of the upgrade or merge of /etc
,
file
will stop working. To fix this,
run:
#
cd /usr/src/usr.bin/file
#
make all install
It depends upon the nature of the change. For example, if svn only shows the following files as being updated:
src/games/cribbage/instr.c
src/games/sail/pl_main.c
src/release/sysinstall/config.c
src/release/sysinstall/media.c
src/share/mk/bsd.port.mk
it probably is not worth rebuilding the entire
world. Instead, go into the appropriate sub-directories
and run make all install
. But if
something major changes, such as
src/lib/libc/stdlib
, consider
rebuilding world.
Some users rebuild world every fortnight and let changes accumulate over that fortnight. Others only re-make those things that have changed and are careful to spot all the dependencies. It all depends on how often a user wants to upgrade and whether they are tracking FreeBSD-STABLE or FreeBSD-CURRENT.
This normally indicates a hardware problem. Building world is an effective way to stress test hardware, especially memory. A sure indicator of a hardware issue is when make is restarted and it dies at a different point in the process.
To resolve this error, swap out the components in the machine, starting with RAM, to determine which component is failing.
/usr/obj
?This directory contains all the object files that
were produced during the compilation phase. Normally,
one of the first steps in the make
buildworld
process is to remove this
directory and start afresh. Keeping
/usr/obj
around when finished makes
little sense, and its removal frees up a approximately
2GB of disk space.
This depends on how far into the process the
problem occurs. In general, make
buildworld
builds new copies of essential
tools and the system libraries. These tools and
libraries are then installed, used to rebuild
themselves, and are installed again. The rest of the
system is then rebuilt with the new system
tools.
During the last stage, it is fairly safe to run
these commands as they will not undo the work of the
previous make buildworld
:
#
cd /usr/src
#
make -DNO_CLEAN all
If this message appears:
--------------------------------------------------------------
Building everything..
--------------------------------------------------------------
in the make buildworld
output,
it is probably fairly safe to do so.
If that message is not displayed, it is always better to be safe than sorry and to restart the build from scratch.
Several actions can speed up the build world process. For example, the entire process can be run from single-user mode. However, this will prevent users from having access to the system until the process is complete.
Careful file system design or the use of ZFS
datasets can make a difference. Consider putting
/usr/src
and
/usr/obj
on
separate file systems. If possible, place the file
systems on separate disks on separate disk controllers.
When mounting /usr/src
, use
noatime
which prevents the file system
from recording the file access time. If /usr/src
is not on its
own file system, consider remounting /usr
with
noatime
.
The file system holding /usr/obj
can be mounted
or remounted with async
so that disk
writes happen asynchronously. The write completes
immediately, and the data is written to the disk a few
seconds later. This allows writes to be clustered
together, and can provide a dramatic performance
boost.
Keep in mind that this option makes the file system more fragile. With this option, there is an increased chance that, should power fail, the file system will be in an unrecoverable state when the machine restarts.
If /usr/obj
is the only
directory on this file system, this is not a problem.
If you have other, valuable data on the same file
system, ensure that there are verified backups before
enabling this option.
Turn off profiling by setting
“NO_PROFILE=true” in
/etc/make.conf
.
Pass -j
to make(1) to run multiple processes in parallel.
This usually helps on both single- and multi-processor
machines.n
First, make absolutely sure that the environment has no extraneous cruft from earlier builds:
#
chflags -R noschg /usr/obj/usr
#
rm -rf /usr/obj/usr
#
cd /usr/src
#
make cleandir
#
make cleandir
Yes, make cleandir
really should
be run twice.
Then, restart the whole process, starting with
make buildworld
.
If problems persist, send the error and the output
of uname -a
to FreeBSD general questions mailing list. Be
prepared to answer other questions about the
setup!
本文及其他文件,可由此下載: ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/。
若有 FreeBSD 方面疑問,請先閱讀
FreeBSD 相關文件,如不能解決的話,再洽詢
<questions@FreeBSD.org>。
關於本文件的問題,請洽詢
<doc@FreeBSD.org>。